1. Field
A positive active material and a rechargeable lithium battery including the same are disclosed.
2. Description of the Related Art
Batteries convert chemical energy generated from an electrochemical redox reaction of chemical material in a battery into electrical energy. Such batteries can be classified into a primary battery, which is generally disposed after the energy inside the battery is consumed, and a rechargeable battery, which can be recharged several times.
A rechargeable battery can be charged/discharged several times as a result of the reversible transformation between chemical energy and electrical energy. Recent developments in the high-tech electronics industry has allowed electronic devices to become small and light weight, which has led to an increase in portable electronic devices. As a power source for such portable electronic devices, the demand for batteries with high energy density is increasing and much research has been directed to developing lithium rechargeable batteries.
A rechargeable lithium battery is manufactured by injecting an electrolyte into a battery cell, which includes a positive electrode including a positive active material capable of intercalating/deintercalating lithium ions and a negative electrode including a negative active material capable of intercalating/deintercalating lithium ions. The positive active material includes a lithium-containing compound capable of reversibly intercalating and deintercalating lithium, for example, a lithium cobalt oxide, a lithium manganese oxide, a lithium nickel compound, or the like. Recently, LiFePO4, having an olivine structure, has been researched as a positive active material. LiFePO4 is chemically stable, and thus is less likely to explode, and is relatively less expensive than other positive active materials. However, LiFePO4 has relatively low ion conductivity and thus, may have decreased capacity when current per unit time is increased.